text: import _concat from './internal/_concat.js';
  import _curry3 from './internal/_curry3.js';
  import uniqWith from './uniqWith.js';
  
  
  /**
   * Combines two lists into a set (i.e. no duplicates) composed of the elements
   * of each list. Duplication is determined according to the value returned by
   * applying the supplied predicate to two list elements. If an element exists
   * in both lists, the first element from the first list will be used.
   *
   * @func
   * @memberOf R
   * @since v0.1.0
   * @category Relation
   * @sig ((a, a) -> Boolean) -> [*] -> [*] -> [*]
   * @param {Function} pred A predicate used to test whether two items are equal.
   * @param {Array} list1 The first list.
   * @param {Array} list2 The second list.
   * @return {Array} The first and second lists concatenated, with
   *         duplicates removed.
   * @see R.union
   * @example
   *
   *      const l1 = [{a: 1}, {a: 2}];
   *      const l2 = [{a: 1}, {a: 4}];
   *      R.unionWith(R.eqBy(R.prop('a')), l1, l2); //=> [{a: 1}, {a: 2}, {a: 4}]
   */
  var unionWith = _curry3(function unionWith(pred, list1, list2) {
    return uniqWith(pred, _concat(list1, list2));
  });
  export default unionWith;
  